(Vapour + liquid) equilibria (VLE) data of (1-butanol + benzene, or toluene, or o-, or m-, or p-xylene) measured by the static method at T = (308.15 +/- 0.01) K over the entire composition range are reported. The excess molar Gibbs free energies of mixing G(m)(E) for these binary systems have been calculated from total vapour pressure data using Barker's method. The G(m)(E) for these binary systems are also analyzed in terms of the Mecke-Kempter type of association model with a Flory contribution term using two interaction parameters and it has been found that this model describes well the G(m)(E) values of these binary systems. (C) 2004 Elsevier Ltd. All rights reserved.